In medicine and ecology the expression "contamination" generally relates to the contamination of food, objects and areas as well as air, water and soil by microorganisms, industrial discharge, exhaust gases and radioactive materials. Contamination by microorganisms, industrial discharge and exhaust gases has been known and has been the object of research for some time already. In many instances, countermeasures have already been found and equipment for preventing such contamination has been developed. Contamination by radioactive materials however has been occurring only more recently and has been observed at an increased rate as radioactive materials find increasing use in industry as well as in medicine. In the past, for example, open waste baskets with foot-operable lids into which paper or plastic bags were inserted for the reception of contaminated materials were considered sufficient. However, especially for disposal of radioactive materials, such equipment is no longer acceptable. Radioactive materials can be present as floating small particles or aerosols thereby spreading their effectiveness over a large area. With the radioactive particles, dangerous radiation may also be widely spread. The radiation emitted by such radioactive materials is usually .alpha., .beta. and .gamma. radiation. Alpha and Beta radiation may be shielded effectively in a relatively simple manner or at least may be weakened to such a degree that there is no serious danger for people. Gamma radiation, however, requires special provisions in order to keep exposure of people as low as possible.
With this precaution in view, present provisions and apparatus for the storing and discarding of industrial chemical waste materials are not adequate for the storing and discarding of exposed radioactive waste materials. Weak radioactive waste materials are mainly generated by the use of radioactive materials in medicine, in medical and biological research and during other scientific research projects. Such waste materials comprise usually solid waste such as containers, test tubes, pipettes, etc., and liquid waste materials such as solvents, dead bodies, waste water and the like. A substantial portion of such waste materials resides in decomposable materials such as contaminated bodies of test animals or soaked bandage materials.
According to presently valid radiation protection rules, radioactive waste materials must be delivered for disposal to officially admitted installations. Before delivery however the waste materials are collected, packaged and stored by the waste generator until they are shipped. If the radioactive materials have only short half lives, the radioactivity of the radioactive materials will diminish during such provisional storage to such a degree that the waste materials may no longer be considered to be radioactively contaminated. In any case, however, the radioactive materials must first be placed into sealed plastic bags to contain radioactive materials and to prevent escape of microorganisms (bacteria and viruses) as well as floating radioactive particles and aerosols.
Present handling practices for contaminated materials are without adequate precautions. A relatively large part of generators of contaminated materials are still using lid-covered baskets into which plastic bags are inserted which, when filled, are simply closed at the top and maintained closed by twist-ties.
It is pointed out that plastic bags, when placed into baskets, are fully opened at their top end for the reception of waste material so that microorganism or other floating parts and aerosols may easily escape whenever the basket lid is opened. There is also the danger of radiation exposure if unconsolidated radioactive waste materials are deposited in the plastic bag. Especially great is the chance of contamination when the plastic bag is closed by a worker since, during this process, air is forced out of the plastic bag, which air may carry a substantial amount of contaminated floating particles or microorganisms toward the worker. Under these circumstances, there is not only a danger of surface contamination but contaminated particles are likely to be inhaled.
It is an object of the present invention to prevent contamination of handling personnel. It is pointed out that contaminated waste materials are deposited in interim storage facilities and are retained there until their radioactivity is subsiding. Such interim storage requires specially adapted chambers with relatively expensive equipment and shielding. The interim storage should therefore require only minimum space. In accordance with prior art practice, however, the plastic bags contain, in volume, about 80% air such that these expensive storage chambers actually contain, when filled, only 20% contaminated waste materials.
It is therefore another object of the present invention to package the waste material for only a minimum volume, that is, to avoid air enclosure in the plastic bags containing the waste materials.
In the prior art, such waste materials are also known to be filled directly into 200 l. barrels which are closed automatically without the presence of a person. In this case, no person is subjected to contamination but a relatively large amount of air is still enclosed in these barrels. Therefore, the waste materials are sometimes shredded or compacted by a compactor so as to reduce volume. However, such equipment is voluminous and therefore cannot be used in laboratories so that the contaminated materials need first to be disposed in smaller bags which then are collected and brought to a shredder or compactor. However, the smaller bags are handled manually, causing the very problem described before, before they arrive at the site equipped for automatic disposal.